As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN ENGINE INTAKE SELECTED ON #1 SIDE, BYPASS DOOR REMAINS CLOSED, HEATER STILL COMES ON. DIVERTED AND ACCOMPLISHED UNEVENTFUL LANDING. REMOVED FROM SERVICE. CONFIRMED WHEN ENGINE INTAKE SELECTED ON #1 SIDE THE DOOR DOES NOT OPEN + ACTUATOR CONTINUOUSLY RUNS, BUT DOES NOT OPEN OR CLOSE THE DOOR. REPLACED #1 ENGINE INTAKE BYPASS DOOR ACTUATOR REF. Q400 AMM TASKS 71-61-01-000/400-801. OPS TEST GOOD. NO FURTHER DEFECTS NOTED. RETURNED TO SERVICE.